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At least 1,027 records · Page 57Linked to original sources
PubMed2005

Influence of culture conditions on laccase production and isozyme patterns in the white-rot fungus Trametes gallica.

Laccase production by the white-rot fungus Trametes gallica was studied, using twelve different media under static or shaking condition. The results indicated that organic nitrogen sources such as tryptone and peptone strongly improved laccase production. The application of an amino acid mixture and a lignin preparation also increased the formation of laccase, which was not observed in the presence of potato extract. Native polyacryl amide gel electrophoresis (PAGE) followed by laccase activity staining using guaiacol as the substrate was performed to analyze the laccase isozyme patterns under the different culture conditions employed. Zymograms revealed a total of twenty different laccase activity bands that appeared in individual patterns, dependent on the respective culture condition applied. This indicates that both the medium composition and the mode of incubation (static or shaking) influenced the laccase isozyme gene expression. This was the first time to report so many laccase isozymes in a fungus. Native PAGE with silver staining showed that laccases were the main protein productions in several media providing a potentially convenient way in purifying laccases from T. gallica.

Amino Acids↗
PubMed1997

Optimization of catalase biosynthesis in submerged cultures of Aspergillus niger mutant.

The effect of some medium components, viscous substances and metabolic inhibitors, on catalase production by mutant Aspergillus niger has been studied in shake culture. Altering the composition of the basal medium, particularly substituting NaNO3 for KNO3, and peptone for yeast extract brought an increase in extra- and intracellular catalase activity by 1.5- and 3-fold, respectively. The addition of 2.0-6.0 mg sodium alginate or pectin/ml as viscous additive to the medium, containing glucose as carbon source, increased the medium viscosity and catalase production in shake culture by about 2.8- to 3.0-fold. The highest yield of extracellular catalase activity of A. niger was obtained in the presence of sodium orthovanadate and Triton X-100, which improved the activity of this enzyme by about 1.5-2.2-fold. A significant increase in intracellular catalase activity was observed in the presence of hematin, Tween 80 and sodium orthovanadate (1.7-, 1.6- and 1.4-fold respectively). The time course of growth and enzyme production by A. niger in the optimized medium is also reported.

Alginates↗
PubMed1998

Production of a novel pyranose 2-oxidase by basidiomycete Trametes multicolor.

During a screening for the enzyme pyranose 2-oxidase (P2O) which has a great potential as a biocatalyst for carbohydrate transformations, Trametes multicolor was identified as a promising, not-yet-described producer of this particular enzyme activity. Furthermore, it was found in this screening that the enzyme frequently occurs in basidiomycetes. Intracellular P2O was produced in a growth-associated manner by T. multicolor during growth on various substrates, including mono-, oligo-, and polysaccharides. Highest levels of this enzyme activity were formed when lactose or whey were used as substrates. Peptones from casein and other casein hydrolysates were found to be the most favorable nitrogen sources for the formation of P2O. By applying an appropriate feeding strategy for the substrate lactose, which ensured an elevated concentration of the carbon source during the entire cultivation, levels of P2O activity obtained in laboratory fermentations, as well as the productivity of these bioprocess experiments, could be enhanced more than 2.5-fold.

Basidiomycota↗
PubMed1996

Mathematical description of the growth of Lactobacillus sake and Lactobacillus pentosus under conditions prevailing in fermented sausages.

The growth behaviour of Lactobacillus sake and Lactobacillus pentosus was determined in a model system stimulating the conditions of fermenting sausages. Minor effects on the growth were observed by varying the concentrations of glucose, peptone, manganese and sodium nitrite. Temperature and sodium chloride concentration were found to have most effect on the growth. The measured data were used for a mathematical model describing the growth response of L. sake and L. pentosus sufficiently well to estimate the behaviour of the investigated strains. In all combinations relevant to sausage fermentation L. sake proved to be more competitive. It exhibited a shorter lag phase, higher maximal growth rate and higher final cell yield than L. pentosus.

Fermentation↗
PubMed1978

The effects of various stimuli on the cellular composition of peritoneal exudates in the mouse.

A comparative study on the composition of cell populations collected from the unstimulated mouse peritoneal cavity and at various intervals after the intraperitoneal injection of glycerol trioleate, casein, paraffin oil, glycogen, sodium chloride, and proteose peptone, was carried out. The cellular composition of the peritoneal exudates, especially with respect to the ratio of monocytes to resident macrophages, was shown to be dependent on the nature of the stimulus and interval after stimulation.

Animals↗
PubMed1989

Pharmacokinetic and pharmacodynamic studies in man simulating acute and chronic treatment with oral pirenzepine.

Nine healthy, male subjects received controlled-rate i.v. infusions of a new formulation of pirenzepine to produce constant plasma levels of 40 ng/ml and 105 ng/ml. They also received stepped infusions resulting in plasma levels of 20, 40, 80 and 40 ng/ml for defined periods. Peptone-stimulated gastric acid and volume secretion and near point vision decreased dose dependently, whereas gastric acidity was unchanged. There was a significant correlation between inhibition of gastric acid secretion and the pirenzepine concentration in plasma and in gastric juice. During the stepped i.v. infusion, changes in near point vision were closely related to the plasma drug concentration. Antimuscarinic side-effects occurred more frequently when the plasma drug level was high. Overall, there was a close relationship between the plasma concentrations and the effects and side-effects of pirenzepine. Its gastric inhibitory action was characterized only by a reduction in gastric volume secretion. Increasing plasma concentrations during the first days of treatment may be essential for its efficacy as an antiulcer drug.

Adult↗
PubMed1987

Effects of FCE20700, a new PGE2 derivative, on gastric acid secretion and cytoprotective processes in man.

The pharmacodynamic effects of FCE20700, a new PGE2 derivative, have been investigated in 6 healthy volunteers given single intragastric (i.g.) and intraduodenal (i.d.) doses of 1 and 2 mg and placebo, according to a double-blind, within-subjects design. For 30-270 min following i.g. administration the effect of FCE20700 on peptone-stimulated gastric acid secretion (AS) was assessed by i.g. titration, and serum gastrin (G) levels were also determined. For the same period after i.d. dosing the effect of the compound on pentagastrin-stimulated AS and on mucoproteins and bicarbonate content in the gastric juice was measured. Blood pressure (BP), heart rate and possible side-effects were monitored. Following i.g. administration there was a moderate, dose-related, significant inhibition of AS; significant inhibition of G levels was observed only after the highest dose. After i.d. administration there was a very modest though dose-related and significant inhibition of AS; a brief maximal increase in mucoproteins and in bicarbonate levels was apparent after the 1 mg dose. After i.d. but not after i.g. administration of 2 mg there was a modest but significant decrease in BP. No side-effects of clinical relevance were reported. The results appear to suggest a major activity of FCE20700 on cytoprotection rather than in inhibiting gastric acid secretion. The observed change in BP may indicate that after i.d. administration there will be some systemic effects of FCE20700.

Adult↗
PubMed1993

Effects of aging on gastrin and somatostatin secretion from isolated perfused rat stomach.

We have examined the release of gastrin and somatostatin from the isolated perfused stomach of rats of three different age groups (4 months, 12 months, and 24 months old) in response to bombesin and carbachol. The basal release of gastrin was diminished in 24-month-old rats. Basal somatostatin release showed an age-related decrease. Bombesin (10(-10) and 10(-9) M) and carbachol (10(-8) and 10(-7) M) stimulated gastrin release in each age group. The integrated release of gastrin in response to bombesin (10(-10) and 10(-9) M) or carbachol (10(-8) M) did not differ among the three age groups, although integrated gastrin release in response to carbachol (10(-7) M) decreased in 24-month-old rats. Bombesin-stimulated release of somatostatin decreased in 12- and 24-month-old rats. Carbachol inhibited release of somatostatin in each age group. Compared with 4-month-old rats, the inhibition of somatostatin release by carbachol was less in 24-month-old rats at 10(-8) and 10(-7) M, and less in 12-month-old rats at 10(-7) M. The decreased basal gastrin secretion and well-preserved gastrin response were further confirmed in conscious aged rats tested by means of oral gavage with 10% peptone. Our findings indicate that gastrin response to the stimuli is well preserved with aging, whereas the response of somatostatin diminishes in an age-related manner. Aging has different effects on the release of gastrin and somatostatin from the rat stomach.

Aging↗
PubMed1984

Glucose perfusion intragastric titration.

A comparison was made between use of isotonic 0.15 M sodium chloride and 5.8 g/100 ml glucose solutions for measurement of gastric acid secretion by intragastric titration in normal and ulcer subjects. Glucose distention did not cause significantly different acid secretion than saline distention in either group. The total amounts of glucose entering the duodenum over the 3.5-hr study period were 99 g in normal subjects and 122 g in ulcer subjects. In normal subjects, circulating gastrin-related acid secretion curves were not significantly different during endogenous peptone and exogenous G-17 stimulation using either the glucose or the saline meals. This finding provides evidence that glucose meals of this size do not alter sensitivity to gastrin. With glucose meals, inhibition of gastric emptying caused retention of a sufficient volume in the stomach to permit accurate continuous intragastric titration. Saline meals caused pronounced diarrhea which was not seen after glucose meals. Glucose distention intragastric titration allows reliable comparisons of endogenously and exogenously stimulated gastric acid secretion without serious side effects and is especially suitable for studying acid secretion in duodenal ulcer subjects.

Adult↗
PubMed1975

[Some properties of carrier strains of Listeria monocytogenes (author's transl)].

About 60 characteristics have been investigated in 7 hemolyzing and 12 nonhemolyzing strains of L. monocytogenes. From these investigations resulted inter alia that the organism grows well under strictly anaerobic conditions, esculin is split at 45 degrees C,NH3 is produced from peptone, but not from arginin, and H2S can be traced by sufficiently sensitive methods. All strains possess a lipase, muramidase, and deoxyribonuclease, the hemolytic ones only also a lecithinase. Besides, the hemolytic strains only dispose of experimental virulence and of a CAMP factor-like agent. The experimental animal of choice seems to be the conjunctivally infected guinea pig in which a generalized infection develops.

Ammonia↗
PubMed1991

Effect of pH and organic matter on the toxicity of heavy metals to growth of some fungi.

Increasing the pH from 5 to 9 decreased the toxicity of mercuric chloride, zinc sulfate, lead nitrate, copper sulfate and nickel chloride toward the growth of Aspergillus flavus, Penicillium chrysogenum, Cunninghamella echinulata, Myrothecium verrucaria and Phoma humicola. On the other hand, the toxicity of cadmium chloride was increased by the increasing pH. Also increasing the concentration of organic matter (peptone and yeast extract) from 0.5 to 1.5% induced a significant reduction in the toxicity of all heavy metals toward the growth of all test fungi.

Cadmium↗
PubMed2002

Effects of nitrogen sources on bacteriocin production by Enterococcus faecium A 2000.

The production of a novel broad-spectrum antimicrobial peptide enterococcin A 2000, active against Gram-positive and Gram-negative microorganisms including Listeria subsp. and Escherichia coli, by Enterococcus faecium strain A 2000 isolated from the surface of traditional Bulgarian yellow cheese "kash-kaval" is considerably influenced by complex nitrogen sources in the production medium. Medium components, especially peptone and yeast extract, and their concentration contributed to the increase in bacteriocin production during the stationary phase (16-46 h) of cultivation even in the absence of one of the components present in the basal cultivation MRS medium.

Bacteriocins↗
PubMed1975

Gluconic acid production by Penicillium puberulum.

Twenty-five Penicillium species isolated from Egyptian soil were examined for their ability to produce gluconic acid in surface culture. Of the eight species capable of producing gluconic acid, Penicillium puberulum gave the maximum yield (91% gluconic acid from glucose after 7 days of fermentation with 3% CaCO3). Peptone was the best nitrogen source for acid fermentation and glucose was superior to sucrose. Addition of low concentrations of KH2PO4 and MgSO4 - 7 H2O stimulated acid production. An initial pH of 6.1 was most favourable for acid accumulation and addition of CaCO3 was necessary for maximum acid production.

Calcium Carbonate↗
PubMed2006

Chlorobium chlorochromatii sp. nov., a symbiotic green sulfur bacterium isolated from the phototrophic consortium "Chlorochromatium aggregatum".

A symbiotic green sulfur bacterium, strain CaD, was isolated from an enrichment culture of the phototrophic consortium "Chlorochromatium aggregatum". The capability of the epibiont to grow in pure culture indicates that it is not obligately symbiotic. Cells are Gram-negative, nonmotile, rod-shaped and contain chlorosomes. Strain CaD is obligately anaerobic and photolithoautotrophic, using sulfide as electron donor. Acetate and peptone are photoassimilated in the presence of sulfide and hydrogencarbonate. Photosynthetic pigments contain bacteriochlorophylls a and c, and gamma-carotene and OH-gamma-carotene glucoside laurate as the dominant carotenoids. In cells from pure cultures, chlorosomes are equally distributed along the inner face of the cytoplasmic membrane. In contrast, the distribution of the chlorosomes in symbiotic epibiont cells is uneven, with chlorosomes being entirely absent at the site of attachment to the central bacterium. The symbiotic epibiont cells display a conspicuous additional layered structure at the attachment site. The G + C content of genomic DNA of strain CaD is 46.7 mol%. On the basis of 16S rRNA sequence comparison, the strain is distantly related to Chlorobium species within the green sulfur bacteria phylum (<or=94.6% sequence homology). The novel isolate is therefore described as a novel species within the genus Chlorobium, Chlorobium chlorochromatii.

Acetic Acid↗
PubMed2006

The role of reduced iron powder in the fermentative production of tetanus toxin.

When tetanus toxin is made by fermentation with Clostridium tetani, the traditional source of iron is an insoluble preparation called reduced iron powder. This material removes oxygen from the system by forming FeO(2) (rust). When inoculated in a newly developed medium lacking animal and dairy products and containing glucose, soy-peptone, and inorganic salts, growth and toxin production were poor without reduced iron powder. The optimum concentration of reduced iron powder for toxin production was found to be 0.5 g/l. Growth was further increased by higher concentrations, but toxin production decreased. Inorganic iron sources failed to replace reduced iron powder for growth or toxin formation. The iron source that came closest was ferrous ammonium sulfate. The organic iron sources ferric citrate and ferrous gluconate were more active than the inorganic compounds but could not replace reduced iron powder. Insoluble iron sources, such as iron wire, iron foil, and activated charcoal, were surprisingly active. Combinations of activated charcoal with soluble iron sources such as ferrous sulfate, ferric citrate, and ferrous gluconate showed increased activity, and the ferrous gluconate combination almost replaced reduced iron powder. It thus appears that the traditional iron source, reduced iron powder, plays a double role in supporting tetanus toxin formation, i.e., releasing soluble sources of iron and providing an insoluble surface.

Clostridium tetani↗
PubMed2007

Effect of culture conditions on antifouling compound production of a sponge-associated fungus.

Microorganisms associated with invertebrate hosts have long been suggested to be a source for bioactive metabolites. In this study, we reported that a sponge-associated fungus, Letendraea helminthicola, produced two antifouling compounds: 3-methyl-N-(2-phenylethyl) butanamide and cyclo(D-Pro-D-Phe). To optimize the production of these antifouling compounds, we then examined the production of compounds under different culture conditions (temperature, salinity, pH, and carbon and nitrogen sources). This fungus grew well and produced more compounds at temperatures between 18 and 30 degrees C; the fungus grew well at 75 parts per thousand (ppt) salinity but produced the highest amount of antifouling compounds at 30 and 45 ppt. The optimal initial pH value for mycelial growth was 5.5 to 6.5, whereas the production of the antifouling compounds was maximized at pH 3.5 and 4.5. Glucose and xylose (as carbon sources) increased the production of antifouling compounds. Yeast extract and peptone (as nitrogen sources) maximized the production of mycelial biomass and antifouling compounds. Our results indicate that culture conditions greatly affect the production of bioactive compounds from mycelial fungal cultures as exemplified by strain L. helminthicola and that the conditions favorable for fungal growth may not be the best conditions for bioactive compound production.

Animals↗
PubMed2005

Effects of carbon and nitrogen sources, carbon-to-nitrogen ratio, and initial pH on the growth of nematophagous fungus Pochonia chlamydosporia in liquid culture.

The effects of carbon and nitrogen sources, carbon-to-nitrogen ratio (C:N) and initial pH value on the growth and sporulation of the nematophagous fungus Pochonia chlamydosporia in liquid culture were examined. Among the 21 carbon sources and 15 nitrogen compounds tested, the optimal carbon and nitrogen sources for mycelial growth were sweet potato and L: -tyrosine, and for sporulation were sweet potato and casein peptone. A C:N ratio of 10:1 at pH 3.7 gave the maximum yield of conidia and a C:N ratio of 40:1 at pH 6.8 gave the maximum biomass. The initial pH value had a significant effect on mycelial growth and conidial production, with the optimal ranges being 3.5-4.5 for sporulation and 5-6 for growth. Maximum conidial production was obtained at an initial pH of 4.0 and the maximum biomass at pH 6.0. The results also showed that the final pH after 7 days cultivation was always higher than the initial value. The variability in growth and sporulation of seven strains of P. chlamydosporia in liquid culture was also compared and discussed.

Biomass↗